Compositions suitable for use as gas and power producing liquids



jet propelled devices.

atmospheric temperatures.

Patented Nov. 30, 1948 COMPOSITIONS SUITABLE FOR USE As GAS anorownn- PRopUo NG LIQUIDS ohn'. WhetstoneflWest Kilbrideytand James ETaywlor, Saltceats, wScotland 'assignors :to imperial .Chemical Industries Limited, .a corporation of Great Britain *No 5 Drawing. ApplicationGI uly 17; 1-946, Serial No. 684 242. IflGreat Britain'-Augusjt 24, l945 positions or otherwise for instance in internal combustion engines or in reaction propelled or It is an object of the invention to provide chemically stable non-vo1atile.power producing compositions that are liquid at or aboutordinary It is known that ammonium nitrate oan-"react with liquid ammoniatatosformi Diver's liquid, but this-liquid is unstable-xandthas a-considerable vapourwpressure of'ammonia.

Ammonium-1' nitrate. :is the most: important energy and gas-producinglsalt used in the explosives industry; and can-also-v be employedin conjunction with oxidisable materials for the ep'roduction of power other wayszithan by explosion,.but-.to a,

certain extent the crystalline formz'of thiscompound limits its application. For instance the amount of ammonium nitrate that can be included in nitroglycerine gelatine explosive compositions is limited rather by thenecessity of E maintaining the proper compactness of the ex- .plosive than by the considerations: of sensitiveness. Again, fuels for internal combustion en-.

gines must be liquids capable of "flow at ordinary or only slightly raised temperatures. To dissolve theammonium nitrate in water would-seriously detract from. the .power. producing. value. of the composition. -Aachemically stable substantially anhydrous homogeneous composition. containing the ammonium nitrateianda material oxidisable by it in solution: at or. about -room-temperatures would thus be of considerable value as a :power producing liquid; but so faras-we' are awaresuch liquid has never beenipr-oduced.

It is known "that ammonium nitrate andxurea form a binary eutectic having ameltingpoint of 443 and containing 47% urea (Howells, Journ.

Chem. Soc. 1929, p. 91'0) and that a ternary eutectic can be formed containing 45% .urea, 4 7.5% ammonium nitrate and 7.5% sodiumnitrate and having a melting point of "37.1? Iii-Iowells, Journ. Chem. Soc. l93'0,.p..'2010). .Itisalso known that a ternary eutectichavinga melting point of 425 can be produced from 45.5% urea, 52.0% ammonium nitrate and 2.5% "resorcinol (HrynakowskiZJKrist' 94, p. 858 (1938) We have nowfo-und 'that'by theirrclusion of one or more compounds of the kind hereina'fterdefined in mixtures containing ammonium" nitrate and'urealit isfpossible to'provide substantially an- 2 hydrous wchemicallystable non-volatile eutectic andinon-eutectic compositions that are liquidat temperatures notsubstantially :higher than: room temperature.

The one or more compounds which are to be included in the ammonium nitrate-urea compositions are ammonium nitrate fusion point depressing inorganic-sal-ts and organicma'terials which are of-low molecular weight and are freely soluble -in-fused-ammonium nitrate and urea; are. not highly associatedin ammonium nitrate solution (such substancesvare usually found to be freely water solublein the cold); do not form insoluble or sparsely soluble salts by decomposition with ammonium nitrate, or. by: co-ordination with urea, to an extent that the'desired reduction in the fusiompoint oi the ammonium nitrate urea eutectic or composition is not attained. The following are examples of suitable .com- :pounds which can be added preferably two or more than two at a time to ammonium nitrate :and urea mixtures namely ammonium sulphamate, ammonium thiosulphate, ammonium formate, ammonium acetate, ammonium thiocyanate, ammonium hypopliosphite, acetamide, propionamide, anhydrous sodium acetate, methylam'ine nitrate.

Thefollowing-inorganic salts-are described by Beilstein 'as giving addition compounds with urea. and are thus unsuitable as additions at least in any quantity: sodium-chloride, ammonium chloride, calcium chloride, zinc chloride, cadmium chloride, mercuric chloride, calcium bromide, magnesimn'b'romide, calcium iodide, sodium nitrate," 'silve'rnitrate, "calcium "nitrate; magnesium nitrate.

Thefollowingsubstances which are freelywa- -ter-;soluble and of low molecular weight have been tound to raise .the crystallising temperature of the ammonium nitrate-urea eutectic; sodium perchlorate, ammonium fluoride-urea nitrate, potassium dihydrogen :phosphate. These substances arecthus'unsuitable as additions.

According to the present invention therefore substantially anhydrous homogeneous compositions suitable for use as gas and power producing liquids ofammonium nitrateand =urea inc1ude values of the said anhydrous homogeneous admixtures should not be allowed to become unfavourably negative, the ammonium nitrate content is usually arbitrarily kept in the region of 45-55% and consequently such liquid mixtures are not true eutectic compositions, though their low lusion points are due to the formation of eutectics.

The following are examples of substantially anhydrous homogeneous admixtures according to the invention whereinthe parts are parts by weight.

Example 1 Parts Ammonium nitrate 50 Urea 33 Methylamine nitrate 1'7 The urea and methylamine nitrate together give a liquid containing suspended matter at 20 C. The ammonium nitrate is dissolved in portions and gives a product almost completely liquid at 20 C.

Example 2 Parts Ammonium nitrate 50 Urea 25 Methylamine nitrate 1'7 Ammonium sulphamate 8 The urea, methylamine nitrate and ammonium sulphamate become liquid when mixed together at room temperature. The ammonium nitrate dissolves almost completely on addition. There is little change in the amount of suspended solid between 18 and 55 C. The oxygen value per gram is 0.18.

Example 3 Parts Ammonium nitrate 50, Urea 25 Ammonium formate l5 Ammonium sulphamate On mixing the above four ingredients together at a somewhat raised temperature a slightly viscous liquid is obtained. On cooltng crystallise tion sets in at 17 C. and the temperature rises to 23 C. and the liquid becomes pasty.

The oxygen value per gram is 0.22.

Example 4 Parts Ammonium nitrate 50 Urea 25 Ammonium formate Ammonium hypophosphite 10 The above four ingredients are mixed and fused together at a somewhat raised temperature. A little crystallisation occurs on cooling to 21 C. but the melt is mostly liquid at room temperature.

The oxygen value is 0.25.'

Example 5 A B C Parts Parts Parts Ammonium nitrate. 45 40 50 Urea 30 30 25 Ammonium formate..- 10 15 10 Ammonium acetate 15 15 15 Oxygen value per gram 0. 38 0. 43 0. 33

The mixture A is completely liquid at 20 c. though cooling below 14 C. induces the separation of long-needle-like crystals, probably ammonium nitrate.

Mixture B, containing less ammonium nitrate, is fluid at l0 C.

Mixture C is partly liquid at room temperatures.

The differences in properties according to variations in the ratio of four components are also shown by the following table:

Example 6 Parts Parts Parts Ammonium nitrate 50 45 40 Urea 25 30 30 Ammonium formate 15 15 15 Acetamide 10 l0 15 Oxygen value per gram 0.34 -0.39 0.48

Composition A, on cooling,- first crystallises at 28 C. and is still very fluid at 20 C. The liquid when cooled to 0 C. remains supercooled but on stirring complete solidification ensues with rise of temperature to 15 C.

Composition B is liquid at room temperatures and crystallises partly at 15 C.

Composition C does not crystallise after 48 hours at 10 C.

Example 7 Parts Parts Ammonium nitrate 50 40 25 Y 30 15 15 Acetamide l0 15 Oxygen value per gram 0. 42 0. 55

These two mixtures illustrate once again that the ratio of the four components is of great importance, for whereas mixture A becomes pasty with suspension of crystals at 30 C. mixture B withstands a few hours storage at 10" C. without crystallisation. This is due to supercooling. On prolonged standing at -10 C. the liquid becomes filled with crystals which do not wholly redissolve at room temperatures.

Example 8 Parts Ammonium nitrate 45 Urea 30 Acetamide 10 Ammonium acetate 5 Ammonium formate 10 On mixing the above five ingredients at a somewhat raised temperature a slightly viscous liquid is obtained. On cooling crystallisation sets in at 15 to 20 C.

We claim:

A gas and power producing composition comprising a blend of from 40 to 55 parts by weight of ammonium nitrate, from 25 to 30 parts by Weight of urea, and from 20 to 25 parts by weight UNITED STATES PATENTS of ammonium nitrate freezing point depressants Number Name Date elected fro the group consisting of ammonium 1,968,153 Naoum July 31, 1934 sulphamate, ammonium thiosulphate, ammonium 5 2,154316 Tyre 11, 1939 formate, ammonium acetate, ammonium thiO- 2,159,234 Taylor May 23, 1939 cyanate, ammonium hypophosphite, acetamide, 2,353,147 Cook July 11, 1944 propionamide, and methylamine nitrate, said blend having a fusion point in the range of GN PATENTS 10 to +30 C. 10 Number Country Date JOH W N 574 Great Britain AD 1875 JAMES TAYLOR. 307,040 Germany Oct. 27, 1919 326,184 Germany Sept. 23, 1920 REFERENCES CITED 380,885 Germany Sept. 10, 1923 The following references are of record in the 15 330,336 Germany p 1923 file of this patent: 

